Energywell p6 & viofo hk4 cutoff voltage.

[-orion-]

Hi everyone, this my first post on the forum.

Rcently i upgraded my trusty vifo 119v2 which I have been using for 5+ years to the new flagship a329 2ch.

Having previously hardwired the old dashcam I also hardwired the new one. I am using a viofo hk4 adapter to power the a329 2ch. I noticed that the parking Mode of the New dashcam is significantly shorter recording just ~1 hour after an hour of driving when the cutoff was set to 12V, likely due to higher power draw of a 2ch 4k compared to a 1ch 1440p. My car is a diesel and in Winter 12V cutoff is allready too low.

I want to enhance the parking Mode by adding the energywell p6 powerbank which I can get brand new for ~$150 so less than half the price of other brands of comparable capacity etc. but power still has to pass through the hk4 adapter which can't be set to less than 11.8V.l cutoff value.

The question is following:
Does anyone know how much power is left in an energy well p6 at 11.8v? If its 10-20% that's fine I do not want to discharge it to 0, but if its e.g 50% the this May be a problem.

I have read that some more expensive power banks actually stabilize the output voltage till the lifepo cells are empty but the energywell supposedly does not and it outputs directly from the battery thus the issue of how much power is still left at 11.8V

Additionaly, does anyone know is it possible to somehow modify a hk4 to lower the cutoff or disable the cutoff altogether so it doesnt do anything even at e.g 11V?


Your help is apprediated
Thanks

 

[EricSan]

Hi and welcome to the forums!

You can message Viofo customer support here on the forum (@VIOFO-Support ) and ask them to send you one of their new HK4 hard wire kits that does not have the voltage cutoff circuit. I haven't looked to see if this new regulator is available on their webpage or not.

Sorry not have any knowledge of the Energy well P6...

 

[Nigel]

Does anyone know how much power is left in an energy well p6 at 11.8v? If its 10-20% that's fine I do not want to discharge it to 0, but if its e.g 50% the this May be a problem.

It will depend a bit on temperature, on how much current is being drawn, and at what voltage the battery pack turns itself off, but it will be very roughly 20 minutes of record time.
Of course, if you have only charged it to 50% since the last cutoff, it will make no difference to record time.

11.8V is at the point where a LiFePO4 starts to loose voltage quickly, to get much more out of it you need to completely empty it, which is not very good for for a lithium battery, 11.8V is a good cutoff for a long lifetime.

If you regularly empty it, and it spends a lot of time empty, then 11.8V will give a longer lifetime, you will only see a record time benefit from a lower cutoff voltage if you charge it to 100%, or very close to 100%, which most people don't do very often.

 

[-orion-]

Thanks for the reply,

I did a Little more research and on several pages saw charts similar to the one below:

It suggests that actually going below 12V is discharging more than 90%, so 11.8V is near zero charge left. Such depth of discharge may influence the number of cycles.

It May be a good idea to actually increase the viofo cutoff from 11.8 to 12V because I have no idea at what cell voltage the energywell bms shuts down.

Thanks for your help, maybe our conclusions will be helpful to someone in the future.

Regards
Orion

 

[Nigel]

It May be a good idea to actually increase the viofo cutoff from 11.8 to 12V

I believe that is unnecessary, because your tables are for an unconnected battery, which will have a slightly higher voltage than one under the load of a dashcam, more so when it has reached the 11.8V point.

These LiFePO4 batteries should do well over 1000 cycles before dropping to 80% original capacity anyway, so if you need the extra 10%, it is reasonable to use it, but unless you are normally filling the battery to 100%, it will be pointless to go below 11.8V. If I'm looking at the correct specification, your battery takes 3 hours to fully charge, so you won't often get to 100%?

 

[Chuck McCoy]

Does anyone know how much power is left in an energy well p6 at 11.8v? If its 10-20% that's fine I do not want to discharge it to 0, but if its e.g 50% the this May be a problem.

Welcome to the club.
@Energywell Can you explain to @-orion- the BMA (battery management system) is in full control of the LiFePo4 cells, and that he should use a hardwire kit that has the low voltage cut off disabled?

You can message Viofo customer support here on the forum (@VIOFO-Support ) and ask them to send you one of their new HK4 hard wire kits that does not have the voltage cutoff circuit. I haven't looked to see if this new regulator is available on their webpage or not.

@EricSan is correct.
Contact Viofo, and request a hardwire kit with the low voltage cut off disabled for specific use with dedicated dash cam battery packs.

@Nigel You are going to drive me to drink. lol

 

[Nigel]

the BMA (battery management system) is in full control of the LiFePo4 cells, and that he should use a hardwire kit that has the low voltage cut off disabled?

The BMS will perform a low voltage cutoff if the voltage drops to dangerous levels, but the cutoff is normally set to optimise the amount of power that can be extracted, not to optimise lifespan of the cells. If your battery rarely reaches 100% charge, there is little point in extracting the last bit of power, better to cut off at 11.8V and double the life of the cells. (I don't know if double is accurate, suspect it is more than that.)

 

[Chuck McCoy]

The BMS will perform a low voltage cutoff if the voltage drops to dangerous levels, but the cutoff is normally set to optimise the amount of power that can be extracted, not to optimise lifespan of the cells. If your battery rarely reaches 100% charge, there is little point in extracting the last bit of power, better to cut off at 11.8V and double the life of the cells. (I don't know if double is accurate, suspect it is more than that.)

@Nigel You are going to drive me to drink. lol

 

[-orion-]

Welcome to the club.
@Energywell Can you explain to @-orion- the BMA (battery management system) is in full control of the LiFePo4 cells, and that he should use a hardwire kit that has the low voltage cut off disabled?

@EricSan is correct.
Contact Viofo, and request a hardwire kit with the low voltage cut off disabled for specific use with dedicated dash cam.

I didnt know a version of hk4 without voltage cutoff existed, thanks for the tip I'll reach out to Viofo support.

I believe that is unnecessary, because your tables are for an unconnected battery, which will have a slightly higher voltage than one under the load of a dashcam, more so when it has reached the 11.8V point.

These LiFePO4 batteries should do well over 1000 cycles before dropping to 80% original capacity anyway, so if you need the extra 10%, it is reasonable to use it, but unless you are normally filling the battery to 100%, it will be pointless to go below 11.8V. If I'm looking at the correct specification, your battery takes 3 hours to fully charge, so you won't often get to 100%?

The @Energywell P6 Has officially ~100Wh and a max charge power of 55W so accounting for losses it should charge from e.g 10% to 100% in ~2h.

I intend to set up the a329 in 1fps SNV parking mode to minimize power (it consumes ~2.7W in SNV whereas all other parking modes are ~4W) according to data posted on the forum. This woud give 100Wh/2.7W=37h of record time.

As overnight I park in an underground garage with CCTV I do not need to record overnight or till the battery dies (e.g over a weekend). About 10h of recording when I'm at work is sufficient and it should use up only ~30% of the charge requiring less than 1h to replenish which is rougly my commute to and from work (30 min there and 30 min back). Thus I intend to set the timer on the pack to 10h (the a329 has parking timer for 8 and 12h, not 10 unfortunately).

I am not sure though how the SNV mode works in broad daylight, will need to test and see.

The BMS will perform a low voltage cutoff if the voltage drops to dangerous levels, but the cutoff is normally set to optimise the amount of power that can be extracted, not to optimise lifespan of the cells. If your battery rarely reaches 100% charge, there is little point in extracting the last bit of power, better to cut off at 11.8V and double the life of the cells. (I don't know if double is accurate, suspect it is more than that.)

Having no control over the energywell BMS shutoff value I'd actually prefer to have some sort of "watchdog" ensuring the battery never gets to 0% even in unfavorable conditions (e.g. several short trips which trigger recording for hours but are insufficient for a recharge). If the 11.8V ensures cutoff at ~10% and doubles the number of cycles available I'm more than happy with that.

 

[VIOFO-Support]

Hi everyone, this my first post on the forum.

Rcently i upgraded my trusty vifo 119v2 which I have been using for 5+ years to the new flagship a329 2ch.

Having previously hardwired the old dashcam I also hardwired the new one. I am using a viofo hk4 adapter to power the a329 2ch. I noticed that the parking Mode of the New dashcam is significantly shorter recording just ~1 hour after an hour of driving when the cutoff was set to 12V, likely due to higher power draw of a 2ch 4k compared to a 1ch 1440p. My car is a diesel and in Winter 12V cutoff is allready too low.

I want to enhance the parking Mode by adding the energywell p6 powerbank which I can get brand new for ~$150 so less than half the price of other brands of comparable capacity etc. but power still has to pass through the hk4 adapter which can't be set to less than 11.8V.l cutoff value.

The question is following:
Does anyone know how much power is left in an energy well p6 at 11.8v? If its 10-20% that's fine I do not want to discharge it to 0, but if its e.g 50% the this May be a problem.

I have read that some more expensive power banks actually stabilize the output voltage till the lifepo cells are empty but the energywell supposedly does not and it outputs directly from the battery thus the issue of how much power is still left at 11.8V

Additionaly, does anyone know is it possible to somehow modify a hk4 to lower the cutoff or disable the cutoff altogether so it doesnt do anything even at e.g 11V?


Your help is apprediated
Thanks

We have HK4 hardwire kit without low voltage cut-off function in our warehouse if you need. I will send you a PM.

 

[Nigel]

If the 11.8V ensures cutoff at ~10% and doubles the number of cycles available I'm more than happy with that.

If you only occasionally go to zero then there is no point in worrying about it.
If you do it every night, as many people do, and leave it at zero all weekend, then stopping at 11.8V may well double the life cycles.

I am not sure though how the SNV mode works in broad daylight, will need to test and see.

Identical to the non-SNV mode I think.

1fps is rather slow, a bit slow even for pedestrians in a car park, you may end up choosing faster.

 

[-orion-]

Identical to the non-SNV mode I think.

1fps is rather slow, a bit slow even for pedestrians in a car park, you may end up choosing faster.

Well there has to be something different as the regular timelapse parking mode consumes about 4W of power regardless if its 1, 2, 5 or 10fps and is roughly equal to AED or LBR and the SNV draws just 2.7W icreasing record time by a factor of 1.5.

As I will be driving max 1h per day I'm looking for ways to reduce power draw.

One way would be to simply not record anything white parked underground at my flat. I am not sure thether holding the menu button will suffice a i have a power bank between the car and dashcam and opening/closing the doors make acc fuses hot for 3 minutes.

For the moment i could manualny change the parking timer on the camera or powerpack to e.g 1h at home but thats manual intervention upon each return so quite annoying.

We have HK4 hardwire kit without low voltage cut-off function in our warehouse if you need. I will send you a PM.

Is it possible in a firmware update to use GPS coordinates to tell the dasham to disable parking recording at or close to set location?

 

[-orion-]

This information may be useful to someone:

As discussed in the thread below settin the cutoff at 11.8V leaves ~3Wh in a comparable battery pack so it aligns with the conclusions above that te lowest setting in the hk4 is less than 10% charge left.

Thread 'VIOFO Prototype Hardwire Kit - Test & Review'

Mar 20, 2024

During testing of EGEN dash cam battery packs (@BlackboxMyCar PowerCell 8 & BlackVue B-130X) I discovered the battery packs continue to deliver power down to 10.9 Volts, (indicated by Cellink Neo APP).

The @viofo hardwire kit has 4 settings for Low Voltage Cutoff (LVC) protection;
12.4V
12.2V
12.0V
11.8V
This means when the lowest LVC setting is used, (11.8V) the hardwire kit will shut off power to the dash cam prematurely, and prevent the battery pack from delivering its full capacity (96Wh).
In July 2023 @rcg530 and myself requested a prototype hardwire...

• Chuck McCoy
• Replies: 57
• Forum: Hardwiring and Batteries

•